EDIBLE SEAWEEDS 79 



Seaweeds are somewhat more popular in Europe 

 than in America. Irish moss, dulse, and laver are 

 the algae most widely used in the British Isles and 

 along the coast of the mainland. But nowhere along 

 the coast are marine vegetables so popular as they 

 are in the Orient. 



The energy-yielding food constituents of seaweeds 

 consist chiefly of carbohydrates together with some 

 proteins. Because neither the carbohydrates nor the 

 proteins are completely digested, these foods must 

 be considered as poor sources of energy. 



Their value lies in their antiscorbutic vitamines 

 and in their content of iodine, bromine, and other 

 inorganic elements, especially their calcium, mag- 

 nesium, and potassium salts. Algae have long been 

 used for preventing scurvy and goiter. Peoples 

 whose dietary includes a liberal amount of algae are 

 surprisingly free from goiter and other diseases of 

 the thyroid. For many centuries the Swiss and Chi- 

 nese have eaten seaweeds in order to prevent and 

 cure goiter, but only in recent years has the cause 

 of its value in the prophylaxis of goiter been known 

 to be its iodine content. Algae vary widely in their 

 iodine content, but as a class they contain a great 

 deal more of iodine than other foods. 



They possess one other physiological property 

 which makes them valuable for certain purposes, 

 inasmuch as they add bulk to the food and absorb 

 much water, thus counteracting constipation. Agar 

 and Irish moss are extensively used for this purpose. 

 Because seaweeds produce little heat when digested 



